Hybrid material for organic electroluminescent element, and organic electroluminescent element

Abstract

Provided are: a material for organic electroluminescent elements, which is capable of obtaining an organic EL element that is driven at a low voltage, emits light at high efficiency, has long-life characteristics, and is practically useful; and an organic electroluminescent element obtained using the material. A mixed material for an organic electroluminescent element, which contains a compound represented by general formula (1) and a cyclic azine compound represented by general formula (10), and an organic electroluminescent element formed using the mixed material. And m represents the number of repetitions and is 2 or 3. Ar1 is a substituted or unsubstituted aromatic hydrocarbon group having 6-20 carbon atoms or the like, and R2-R7 are each independently hydrogen, a substituted or unsubstituted aromatic hydrocarbon group having 6-20 carbon atoms or the like. Ar2 and Ar3 are each independently a substituted or unsubstituted C6-20 aromatic hydrocarbon group or the like, and L1 is a single bond or a substituted or unsubstituted phenyl group.

Description

TECHNICAL FIELD

[0001] The present application relates to an organic electroluminescence element (referred to as an organic EL element) that can convert electric energy into light, and a material for the organic electroluminescence element.

[0002] By applying a voltage to an organic electroluminescence (EL) element, holes are injected from an anode to a light-emitting layer, and electrons are injected from a cathode to the light-emitting layer, respectively. Furthermore, in the light-emitting layer, the injected holes and electrons recombine to generate an exciton. At this time, according to a statistical law of electron spin, a singlet exciton and a triplet exciton are generated at a ratio of 1:3. With respect to a fluorescent light-emitting type organic EL element that uses light emission from a singlet exciton, it is considered that the limit of internal quantum efficiency is 25%. On the other hand, it is known that a phosphorescent light-emitting type organic EL element that uses light emission from a triplet exciton improves the internal quantum efficiency to 100% in a case where intersystem crossing from a singlet exciton is efficiently performed.

[0003] In recent years, a long-life technology of a phosphorescent type organic EL element has been advanced, and is being applied to displays of mobile phones and the like. However, with respect to a blue organic EL element, a practical phosphorescent light-emitting type organic EL element has not yet been developed, and thus development of a blue organic EL element that is high in efficiency and long in life is required.

[0004] Further, in recent years, a high-efficiency delayed fluorescent light-emitting type organic EL element that utilizes delayed fluorescence is being developed. For example, in Patent Document 1, an organic EL element that utilizes a triplet-triplet fusion (TTF) mechanism that is one of mechanisms of delayed fluorescence is disclosed. The TTF mechanism utilizes a phenomenon that a singlet exciton is generated by collision of two triplet excitons, and it is considered that the internal quantum efficiency is improved to 40% in theory. However, compared with a phosphorescent light-emitting type organic EL element, the efficiency is low, and thus further improvement of efficiency is required.

[0005] On the other hand, in Patent Document 2, an organic EL element that utilizes a thermally activated delayed fluorescence (TADF) mechanism is disclosed. The TADF mechanism is a mechanism that utilizes a phenomenon that, in a material in which an energy difference between a singlet energy level and a triplet energy level is small, inverse intersystem crossing from a triplet exciton to a singlet exciton occurs, and it is considered that the internal quantum efficiency is improved to 100% in theory.

[0006] Here, in Non-Patent Literature 1, there is disclosed an element which uses a prescribed mixed host (SiTrz2Cz and SiCzCz) in addition to a prescribed phosphorescent dopant and a TADF dopant.

[0007] In addition, in Patent Literature 3, there is disclosed an element which uses a mixed host of a compound having a carbazole skeleton and a compound having an indolocarbazole skeleton.

[0008] Further, in Patent Literature 4, there is disclosed an element which uses a mixed composition containing a compound having a carbazole skeleton and a cyclic azine compound.

[0009] Further, in Patent Literatures 5 to 8, there is disclosed an element which uses a mixed composition containing a compound having a carbazole skeleton and a compound having a triazine skeleton.

[0010] Prior Art Documents

[0011] Patent Literature

[0012] Patent Literature 1: WO2010 / 134350

[0013] Patent Literature 2: WO2011 / 070963

[0014] Patent Literature 3: WO2016 / 158191

[0015] Patent Literature 4: WO2022 / 45272

[0016] Patent Literature 5: WO2021 / 200252

[0017] Patent Literature 6: WO2020 / 218188

[0018] Patent Literature 7: WO2021 / 065492

[0019] Patent Literature 8: WO2012 / 077520

[0020] Non-Patent Literature

[0021] Non-Patent Literature 1: Kim et al., Sci. Adv. 8, eabq1641 (2022) SUMMARY

[0022] PROBLEMS TO BE SOLVED BY THE INVENTION

[0023] In order to use the organic EL element as a display element or a light source for a flat panel display or the like, it is necessary to sufficiently ensure stability at the time of driving while improving the light emission efficiency of the element, but these cannot be achieved with a material containing a combination of the previously known compounds.

[0024] The present application has been achieved in view of such a situation, and aims to provide an organic electroluminescent element material for an organic electroluminescent element, which is practically useful because it can achieve low-voltage driving, emits light with high efficiency, and has long-life characteristics. In addition, the present application aims to provide an organic EL element using such a material.

[0025] Technical means for solving the problem

[0026] That is, the present application is a mixed material for an organic electroluminescent element, characterized by containing a compound represented by the following general formula (1), and a cyclic azine compound represented by the following general formula (10). In addition, the mixed material contains a compound represented by general formula (1) and a compound represented by general formula (10), but general formula (1) and general formula (10) are not the same compound at the same time.

[0027] [Chemical Formula 1]

[0028]

[0029] Here, m represents the number of repetitions and is 2 or 3. Ar 1 represents an aliphatic hydrocarbon group having 1 to 10 carbons, a substituted or unsubstituted triaryl silane group having 18 to 36 carbons, an aromatic hydrocarbon group having 6 to 20 carbons which is substituted or unsubstituted, an aromatic heterocyclic group having 2 to 20 carbons which is substituted or unsubstituted, or a linked aromatic group which is substituted or unsubstituted and is constituted by linking 2 to 3 aromatic groups selected from the aromatic hydrocarbon group and the aromatic heterocyclic group. R 2 ~R 7 independently represent hydrogen, an aliphatic hydrocarbon group having 1 to 10 carbons, a substituted or unsubstituted triaryl silane group having 18 to 36 carbons, an aromatic hydrocarbon group having 6 to 20 carbons which is substituted or unsubstituted, an aromatic heterocyclic group having 2 to 20 carbons which is substituted or unsubstituted, or a linked aromatic group which is substituted or unsubstituted and is constituted by linking 2 to 3 aromatic groups selected from the aromatic hydrocarbon group and the aromatic heterocyclic group. Among them, Ar 1 and R 2 ~R 7 does not contain carbazole. In addition, a part or all of the hydrogens in the compound represented by general formula (1) can be substituted with deuterium.

[0030] [Chemical Formula 2]

[0031]

[0032] Here, Ar 2 and Ar 3 independently represent an aliphatic hydrocarbon group having 1 to 10 carbons, a substituted or unsubstituted triaryl silyl group having 18 to 36 carbons, a substituted or unsubstituted aromatic hydrocarbon group having 6 to 20 carbons, a substituted or unsubstituted aromatic heterocyclic group having 2 to 17 carbons, or a substituted or unsubstituted linked aromatic group formed by linking 2 to 3 aromatic groups selected from the aromatic hydrocarbon group and the aromatic heterocyclic group. L 1 represents a single bond or a substituted or unsubstituted phenyl group. Some or all of the hydrogens in the compound represented by the general formula (10) can be substituted with deuterium.

[0033] The compound represented by the general formula (1) preferably contains at least one of the linking structures represented by any one of the following formulas (2) to (7), and more preferably contains at least two of them. In addition, some or all of the hydrogens in the linking structures represented by the formulas (2) to (7) can be substituted with deuterium. In addition, "in the formulas, " represents the position of the linking to the carbazole or Ar in the general formula (1). Furthermore, the carbazole described in the formulas (2) to (7) can also have substituents corresponding to R 1 to R 2 to R 7 in the general formula (1).

[0034] [Chemical 3]

[0035]

[0036] L 1 in the general formula (10) is preferably a single bond.

[0037] In addition, the present application is an organic electroluminescent element containing one or more organic layers between a pair of an anode and a cathode, characterized in that at least one of the organic layers contains the mixed material for an organic electroluminescent element. The organic layer in the organic electroluminescent element can contain only the compound represented by the general formula (1) and the compound represented by the general formula (10), and these compounds can be supplied to the organic layer individually, or can be supplied as a premix prepared by mixing the compound represented by the general formula (1) and the compound represented by the general formula (10) in advance, that is, as the mixed composition for an organic electroluminescent element.

[0038] In the organic electroluminescent element of the present application, the organic layer containing the mixed material for an organic electroluminescent element is a light-emitting layer, preferably contains a thermally activated delayed fluorescence light-emitting material in the light-emitting layer, and more preferably the thermally activated delayed fluorescence light-emitting material contains a boron atom.

[0039] Further, in the organic electroluminescent device of the present application, the organic layer containing the mixed material for an organic electroluminescent device is a light-emitting layer, preferably contains a phosphorescent light-emitting material in the light-emitting layer, more preferably the phosphorescent light-emitting material contains a platinum atom.

[0040] Further, in the organic electroluminescent device of the present application, the organic layer containing the mixed material for an organic electroluminescent device is a light-emitting layer, and preferably contains the material for an organic electroluminescent device as a host material, and more preferably the light-emitting layer contains a thermally activated delayed fluorescence light-emitting material containing a boron atom and a phosphorescent light-emitting material containing a platinum atom.

[0041] Further, the present application is a method for producing an organic electroluminescent device having a plurality of organic layers between an anode and a cathode, preferably one of the organic layers is a light-emitting layer, and the light-emitting layer is produced by evaporation from one evaporation source using the mixed material for an organic electroluminescent device of the present application.

[0042] Effects of the Invention

[0043] According to the present application, an organic EL device which is practically useful, has a low voltage drive, emits light with high efficiency, and has a long lifetime can be obtained. BRIEF DESCRIPTION OF DRAWINGS

[0044] [ Figure 1 ] Figure 1 is a cross-sectional schematic view showing a structure example of an organic EL device used in the present application. DETAILED DESCRIPTION

[0045] The compound represented by General Formula (1) and the compound represented by General Formula (10) in the present application are described in detail, respectively.

[0046] First, regarding General Formula (1), as described above, m represents the number of repetitions and is 2 or 3. It is preferable that m represents 2.

[0047] Ar 1aliphatic hydrocarbon group having 1 to 10 carbons, a substituted or unsubstituted triaryl silyl group having 18 to 36 carbons, a substituted or unsubstituted aromatic hydrocarbon group having 6 to 20 carbons, a substituted or unsubstituted aromatic heterocyclic group having 2 to 20 carbons, or a substituted or unsubstituted linked aromatic group formed by linking 2 to 3 aromatic groups selected from the aromatic hydrocarbon group and the aromatic heterocyclic group. Preferably, a substituted or unsubstituted aromatic hydrocarbon group having 6 to 15 carbons, a substituted or unsubstituted aromatic heterocyclic group having 2 to 15 carbons, or a substituted or unsubstituted linked aromatic group formed by linking 2 to 3 aromatic groups selected from the aromatic hydrocarbon group and the aromatic heterocyclic group. More preferably, a substituted or unsubstituted aromatic hydrocarbon group having 6 to 15 carbons, or a substituted or unsubstituted linked aromatic group formed by linking 2 to 3 aromatic groups selected from the aromatic hydrocarbon group. Among them, Ar 1 does not include carbazole.

[0048] In addition, R 2 ~ R 7 independently represent hydrogen, an aliphatic hydrocarbon group having 1 to 10 carbons, a substituted or unsubstituted triaryl silyl group having 18 to 36 carbons, a substituted or unsubstituted aromatic hydrocarbon group having 6 to 20 carbons, a substituted or unsubstituted aromatic heterocyclic group having 2 to 20 carbons, or a substituted or unsubstituted linked aromatic group formed by linking 2 to 3 aromatic groups selected from the aromatic hydrocarbon group and the aromatic heterocyclic group. Preferably, a substituted or unsubstituted aromatic hydrocarbon group having 6 to 15 carbons, a substituted or unsubstituted aromatic heterocyclic group having 2 to 15 carbons, or a substituted or unsubstituted linked aromatic group formed by linking 2 to 3 aromatic groups selected from the aromatic hydrocarbon group and the aromatic heterocyclic group. More preferably, a substituted or unsubstituted aromatic hydrocarbon group having 6 to 15 carbons, or a substituted or unsubstituted linked aromatic group formed by linking 2 to 3 aromatic groups selected from the aromatic hydrocarbon group. Among them, R 2 ~ R 7 does not include carbazole.

[0049] In addition, a part or all of hydrogens in the compound represented by General Formula (1) can be substituted with deuterium.

[0050] As for the compound represented by General Formula (1), it is preferable to include at least one of the bonding structures represented by any one of the formulae (2) to (7), and more preferable to include at least two thereof. Among them, as for the compound represented by General Formula (1), it is preferable to include at least one of the bonding structures represented by formula (2) or (3), or at least one of the bonding structures represented by formula (4) or (5), or at least one of the bonding structures represented by formula (6) or (7).

[0051] Further, some or all of the hydrogens in the bonding structures represented by formulae (2) to (7) can be substituted with deuterium. In addition, the formulae indicate the bonding position to the carbazole or Ar 1 in the formula (1).

[0052] On the other hand, as for General Formula (10), as described above, Ar 2 and Ar 3 independently represent an aliphatic hydrocarbon group having a carbon number of 1 to 10, a substituted or unsubstituted triaryl silyl group having a carbon number of 18 to 36, a substituted or unsubstituted aromatic hydrocarbon group having a carbon number of 6 to 20, a substituted or unsubstituted aromatic heterocyclic group having a carbon number of 2 to 17, or a substituted or unsubstituted linked aromatic group consisting of 2 to 3 links of the aromatic groups selected from the aromatic hydrocarbon group and the aromatic heterocyclic group. It is preferable to represent a substituted or unsubstituted aromatic hydrocarbon group having a carbon number of 6 to 15, a substituted or unsubstituted aromatic heterocyclic group having a carbon number of 2 to 15, or a substituted or unsubstituted linked aromatic group consisting of 2 to 3 links of the aromatic groups selected from the aromatic hydrocarbon group and the aromatic heterocyclic group. It is more preferable to represent a substituted or unsubstituted aromatic hydrocarbon group having a carbon number of 6 to 15, or a substituted or unsubstituted linked aromatic group consisting of 2 to 3 links of the aromatic groups selected from the aromatic hydrocarbon group.

[0053] In addition, L 1 represents a single bond or a substituted or unsubstituted phenyl group, and it is preferable to represent a single bond.

[0054] Further, some or all of the hydrogens in the compound represented by General Formula (10) can be substituted with deuterium.

[0055] As the Ar 1 and R 2 to R 7Specific examples of the unsubstituted carbon number 6 to 20 aromatic hydrocarbon group, the unsubstituted carbon number 2 to 20 aromatic heterocyclic group, or the unsubstituted linked aromatic group formed by linking 2 to 3 aromatic groups selected from the aforementioned aromatic hydrocarbon group and the aforementioned aromatic heterocyclic group, can include groups derived from benzene, naphthalene, acenaphthene, acenaphthylene, azulene, anthracene, pyrene, phenanthrene, triphenylene, fluorene, benz[a]anthracene, pyridine, pyrimidine, triazine, thiophene, isothiazole, thiazole, pyridazine, pyrrole, pyrazole, imidazole, triazole, thiadiazole, pyrazine, furan, isoxazole, quinoline, isoquinoline, quinoxaline, quinazoline, thiadiazole, pteridine, tetrazole, indole, benzofuran, benzothiophene, benzoxazole, benzothiazole, indazole, benzimidazole, benzotriazole, benzoisothiazole, benzothiadiazole, purine, pyranone, coumarin, isocoumarin, chromone, diphenylene oxide, diphenylene sulfide, or dibenzoselenophene, or a linked aromatic group formed by linking 2 to 3 of these aromatic groups. Preferably, specific examples can include groups derived from benzene, naphthalene, acenaphthene, acenaphthylene, azulene, anthracene, phenanthrene, fluorene, pyridine, pyrimidine, triazine, thiophene, isothiazole, thiazole, pyridazine, pyrrole, pyrazole, imidazole, triazole, thiadiazole, pyrazine, furan, isoxazole, quinoline, isoquinoline, quinoxaline, quinazoline, thiadiazole, pteridine, tetrazole, indole, benzofuran, benzothiophene, benzoxazole, benzothiazole, indazole, benzimidazole, benzotriazole, benzoisothiazole, benzothiadiazole, purine, pyranone, coumarin, isocoumarin, chromone, diphenylene oxide, diphenylene sulfide, or dibenzoselenophene, or a linked aromatic group formed by linking 2 to 3 of these aromatic groups. More preferably, specific examples can include groups derived from benzene, naphthalene, acenaphthene, acenaphthylene, azulene, anthracene, phenanthrene, or fluorene, or a linked aromatic group formed by linking 2 to 3 of these aromatic groups.

[0056] As the Ar 2 and Ar 3 Specific examples of the unsubstituted carbon number 6 to 20 aromatic hydrocarbon group, the unsubstituted carbon number 2 to 17 aromatic heterocyclic group, or the unsubstituted linked aromatic group formed by linking 2 to 3 aromatic groups selected from the aforementioned aromatic hydrocarbon group and the aforementioned aromatic heterocyclic group, can include groups derived from benzene, naphthalene, acenaphthene, acenaphthylene, azulene, anthracene, pyrene, phenanthrene, triphenylene, fluorene, benz[a]anthracene, pyridine, pyrimidine, triazine, thiophene, isothiazole, thiazole, pyridazine, pyrrole, pyrazole, imidazole, triazole, thiadiazole, pyrazine, furan, isoxazole, quinoline, isoquinoline, quinoxaline, quinazoline, thiadiazole, pteridine, tetrazole, indole, benzofuran, benzothiophene, benzoxazole, benzothiazole, indazole, benzimidazole, benzotriazole, benzoisothiazole, benzothiadiazole, purine, pyranone, coumarin, isocoumarin, chromone, diphenylene oxide, diphenylene sulfide, or dibenzoselenophene, or a linked aromatic group formed by linking 2 to 3 of these aromatic groups. Preferably, specific examples can include groups derived from benzene, naphthalene, acenaphthene, acenaphthylene, azulene, anthracene, phenanthrene, fluorene, pyridine, pyrimidine, triazine, thiophene, isothiazole, thiazole, pyridazine, pyrrole, pyrazole, imidazole, triazole, thiadiazole, pyrazine, furan, isoxazole, quinoline, isoquinoline, quinoxaline, quinazoline, thiadiazole, pteridine, tetrazole, indole, benzofuran, benzothiophene, benzoxazole, benzothiazole, indazole, benzimidazole, benzotriazole, benzoisothiazole, benzothiadiazole, purine, pyranone, coumarin, isocoumarin, chromone, diphenylene oxide, diphenylene sulfide, or dibenzoselenophene, or a linked aromatic group formed by linking 2 to 3 of these aromatic groups. More preferably, specific examples can include groups derived from benzene, naphthalene, acenaphthene, acenaphthylene, azulene, anthracene, phenanthrene, or fluorene, or a linked aromatic group formed by linking 2 to 3 of these aromatic groups. 1 and R 2 ~ R 7The aromatic hydrocarbon group, the aromatic heterocyclic group, or the linked aromatic group can have a substituent. The substituent is preferably deuterium, a halogen, a cyano group, an alkyl group having 1 to 10 carbons, a triaryl silane group having 9 to 30 carbons, an alkenyl group having 2 to 5 carbons, an alkoxy group having 1 to 5 carbons, or a diaryl amino group having 12 to 44 carbons. The triaryl silane group can have a substituent. The substituent is deuterium or an alkyl group having 1 to 10 carbons.

[0057] In addition to the compound represented by the general formula (1), in the present specification, the unsubstituted aromatic hydrocarbon group, the aromatic heterocyclic group, or the linked aromatic group can have a substituent. The substituent when having a substituent is preferably deuterium, a halogen, a cyano group, an alkyl group having 1 to 10 carbons, a triaryl silane group having 9 to 30 carbons, an alkenyl group having 2 to 5 carbons, an alkoxy group having 1 to 5 carbons, or a diaryl amino group having 12 to 44 carbons. In addition, the unsubstituted triaryl silane group can have a substituent. The substituent is deuterium or an alkyl group having 1 to 10 carbons, which substitutes the aryl site of the triaryl silane group.

[0058] In addition, the number of the substituent can be 0 to 5, and is preferably 0 to 2. The calculation of the number of carbons when the aromatic hydrocarbon group, the aromatic heterocyclic group, or the linked aromatic group has a substituent does not include the number of carbons of the substituent. However, the total number of carbons including the number of carbons of the substituent preferably satisfies the range.

[0059] As the substituent, deuterium, a cyano group, a bromine, a fluorine, a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, a tert-butyl group, a pentyl group, a cyclopentyl group, a hexyl group, a cyclohexyl group, a heptyl group, an octyl group, a nonyl group, a decyl group, a triphenyl silane group, a biphenyl diphenyl silane group, a bisbiphenyl phenyl silane group, a trisbiphenyl silane group, a vinyl group, a propenyl group, a butenyl group, a pentenyl group, a methoxy group, an ethoxy group, a propoxy group, a butoxy group, a pentoxy group, a diphenyl amino group, a naphthyl phenyl amino group, a dinaphthyl amino group, a dianthryl amino group, a difenyl amino group, a di-p-quinolyl amino group, and the like can be exemplified. Preferably, deuterium, a cyano group, a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, a heptyl group, an octyl group, a vinyl group, a propenyl group, a butenyl group, a pentenyl group, a methoxy group, an ethoxy group, a propoxy group, a butoxy group, a pentoxy group, a triphenyl silane group can be exemplified.

[0060] In the present specification, a linked aromatic group refers to an aromatic group in which two or more aromatic rings of aromatic groups are linked by a single bond. These linked aromatic groups can be linear or branched. The linking position when benzene rings are linked to each other can be any of the ortho position, the meta position, and the para position, but is preferably para linking or meta linking. The aromatic group can be an aromatic hydrocarbon group or an aromatic heterocyclic group, and the plurality of aromatic groups can be the same or different.

[0061] The mixed material for an organic electroluminescent element in the present application can be a powder or a solid, or a thin film, provided that it contains the compound represented by General Formula (1) and the compound represented by General Formula (10). For example, in the case where the mixed material is used to form a light-emitting layer of an organic EL element, the compound represented by General Formula (1) and the compound represented by General Formula (10) can be supplied to the light-emitting layer individually, or as a premix in which the compound represented by General Formula (1) and the compound represented by General Formula (10) are mixed in advance, i.e., as a mixed composition for an organic electroluminescent element. Among them, it is preferable to provide a premix in which the compound represented by General Formula (1) and the compound represented by General Formula (10) are mixed in advance (i.e., a mixed composition for an organic electroluminescent element).

[0062] The premix (mixed composition) is one form of the mixed material, and the compound represented by General Formula (1) and the compound represented by General Formula (10) can be mixed in a powder state, or can be mixed by melting under reduced pressure or in an inert gas atmosphere such as nitrogen using heating, or can be made by sublimating the mixed compounds together.

[0063] On the other hand, the mixed material containing the compound represented by General Formula (1) and the compound represented by General Formula (10) can be in a powder state or a thin film state. In the case of a thin film state, the compound represented by General Formula (1) and the compound represented by General Formula (10) can be contained in the same organic layer, or can be contained in different organic layers of an element. For example, the compound represented by General Formula (1) can be contained in an electron-blocking layer, and the compound represented by General Formula (10) can be contained in a light-emitting layer.

[0064] For the mixed material for an organic electroluminescent element in the present application, the mixing ratio (mass ratio) of the compound represented by General Formula (1) to the compound represented by General Formula (10) in the material can be 40 mass% to 90 mass%, preferably 50 mass% to 90 mass%, and more preferably 60 mass% to 90 mass%, relative to the total of the compound represented by General Formula (1) and the compound represented by General Formula (10).

[0065] The following show specific examples of compounds represented by General Formula (1), but the present application is not limited to these example compounds.

[0066] [Chemical Formula 4]

[0067]

[0068] [Chemical Formula 5]

[0069]

[0070] [Chemical Formula 6]

[0071]

[0072] [Chemical Formula 7]

[0073]

[0074] [Chemical Formula 8]

[0075]

[0076] [Chemical Formula 9]

[0077]

[0078] [Chemical Formula 10]

[0079]

[0080] [Chemical Formula 11]

[0081]

[0082] [Chemical Formula 12]

[0083]

[0084] [Chemical Formula 13]

[0085]

[0086] In addition, the following show specific examples of compounds represented by General Formula (10), but the present application is not limited to these example compounds.

[0087] [Chemical Formula 14]

[0088]

[0089] [Chemical Formula 15]

[0090]

[0091] [Chemical Formula 16]

[0092]

[0093] [Chem. 17]

[0094]

[0095] [Chem. 18]

[0096]

[0097] [Chem. 19]

[0098]

[0099] [Chem. 20]

[0100]

[0101] [Chem. 21]

[0102]

[0103] By using a mixed material for an organic electroluminescent element containing the compound represented by the general formula (1) and the compound represented by the general formula (10) to form an organic layer, an organic EL element that emits light with high efficiency and has a long lifetime characteristic, which is excellent in practical use, can be produced.

[0104] The organic EL element is preferably one in which at least one organic layer is a light-emitting layer, and the mixed material for an organic electroluminescent element of the present application is contained in the light-emitting layer. Further, an organic EL element in which a thermally activated delayed fluorescence light-emitting material or a phosphorescent light-emitting material is further contained in the light-emitting layer is more preferable, and an organic EL element in which a thermally activated delayed fluorescence light-emitting material is contained in the light-emitting layer is further preferable.

[0105] That is, by containing a thermally activated delayed fluorescence light-emitting material or a phosphorescent light-emitting material and at least one host material in the light-emitting layer as needed, an excellent organic EL element can be produced, but it is preferable that at least one host material is the mixed material for an organic electroluminescent element of the present application.

[0106] At this time, as described above, the compound represented by the general formula (1) and the compound represented by the general formula (10) can be separately produced as powders and pre-mixed in advance, or a mixed composition (pre-mixture) for an organic electroluminescent element produced by pre-mixing using heating and melting of these powders can be used to perform evaporation from one evaporation source, whereby a light-emitting layer of an organic EL element can be produced.

[0107] Next, the structure of the organic EL element of the present application will be described with reference to the drawings, but the structure of the organic EL element of the present application is not limited thereto.

[0108] Figure 1 is a cross-sectional view showing a structure example of a general organic EL element used in the present application, 1 represents a substrate, 2 represents an anode, 3 represents a hole injection layer, 4 represents a hole transport layer, 5 represents a light-emitting layer, 6 represents an electron transport layer, and 7 represents a cathode. In the organic EL element of the present application, the anode, the light-emitting layer, and the cathode are essential layers, but in addition to the essential layers, the hole injection layer, the hole transport layer, the electron transport layer, the electron injection layer, and further, the electron blocking layer between the hole transport layer and the light-emitting layer and the hole blocking layer between the light-emitting layer and the electron transport layer can be provided.

[0109] It can also be a structure opposite to Figure 1 that is, the cathode 7, the electron transport layer 6, the light-emitting layer 5, the hole transport layer 4, the hole injection layer 3, and the anode 2 are sequentially stacked on the substrate 1, in which case, the layers can be added or omitted as necessary. Furthermore, in the organic EL element as described above, layers constituting the stacked structure on the substrate are sometimes collectively referred to as organic layers, in addition to the electrode such as the anode or the cathode.

[0110] -Substrate-

[0111] The organic EL element of the present application is preferably supported on a substrate. The substrate is not particularly limited as long as it is a substrate that has been used for organic EL elements from before, and for example, a substrate including glass, transparent plastic, quartz, or the like can be used.

[0112] -Anode-

[0113] As a material for the anode in the organic EL element, a material containing a metal, an alloy, an electrically conductive compound, or a mixture of these, having a large work function (4 eV or more) can be preferably used. As a specific example of such an electrode material, a metal such as Au; a conductive transparent material such as Cul, indium tin oxide (ITO), Sn02, and ZnO can be given. In addition, an amorphous material such as IDIXO (In203-ZnO) and a material capable of forming a transparent conductive film can also be used. The anode can be formed by forming a thin film of these electrode materials using a method such as evaporation or sputtering, and forming a pattern of a desired shape using photolithography, or in the case where a pattern precision is not required much (100 μm or more), a pattern can be formed by interposing a mask of a desired shape at the time of evaporation or sputtering of the electrode material. Or in the case of using a substance capable of being coated such as an organic conductive compound, a wet film formation method such as a printing method, a coating method, and the like can be used. In the case where light is extracted from the anode, it is desirable that the transmittance be more than 10%, and in addition, the sheet resistance of the anode is preferably several hundred Ω / D or less. The film thickness also depends on the material, and is usually selected in the range of 10 nm to 1000 nm, preferably 10 nm to 200 nm.

[0114] - Cathode -

[0115] On the other hand, as a material for the cathode, a material containing a metal (referred to as an electron- injecting metal), an alloy, an electrically conductive compound, or a mixture of these, having a small work function (4 eV or less) can be used. As a specific example of such an electrode material, sodium, a sodium-potassium alloy, magnesium, lithium, a magnesium / copper mixture, a magnesium / silver mixture, a magnesium / aluminum mixture, a magnesium / indium mixture, an aluminum / aluminum oxide (AI2O3) mixture, indium, a lithium / aluminum mixture, a rare earth metal, and the like can be given. Among these, in terms of electron-injecting property and durability against oxidation and the like, a mixture of an electron-injecting metal and a second metal having a value of work function larger than that of the electron-injecting metal and stable, such as a magnesium / silver mixture, a magnesium / aluminum mixture, a magnesium / indium mixture, an aluminum / aluminum oxide (AI2O3) mixture, a lithium / aluminum mixture, aluminum, and the like is suitable. The cathode can be produced by forming a thin film of these cathode materials using a method such as evaporation or sputtering. In addition, the sheet resistance of the cathode is preferably several hundred Ω / D or less, and the film thickness is usually selected in the range of 10 nm to 5 μm, preferably 50 nm to 200 nm. Furthermore, in order to make the emitted light to be transmitted, if either of the anode or the cathode of the organic EL element is transparent or semi-transparent, the luminance of light emission is improved, and thus is suitable.

[0116] Furthermore, after forming the metal on the cathode with a film thickness of 1 nm to 20 nm, a conductive transparent material listed in the description of the anode is formed on it, thereby making a transparent or semi-transparent cathode. By applying the method described above, an element in which both the anode and cathode are permeable can be made.

[0117] -Emitting Layer-

[0118] The light-emitting layer is a layer that emits light after excitons are generated by the recombination of holes and electrons injected from the anode and cathode, respectively. The light-emitting layer can be a single layer or multiple layers, and includes organic light-emitting dopant materials and host materials.

[0119] The light-emitting layer may contain only one type of organic light-emitting dopant, or it may contain two or more types. The content of the organic light-emitting dopant relative to the host material is preferably 0.1% to 50% by mass, more preferably 0.1% to 40% by mass.

[0120] When using phosphorescent dopant as an organic luminescent dopant material, the phosphorescent dopant may contain an organometallic complex comprising at least one metal selected from ruthenium, rhodium, palladium, silver, rhenium, osmium, iridium, platinum, and gold. Specifically, iridium complexes described in J. Am. Chem. Soc. 2001, 123, 4304 or Japanese Patent Publication No. 2013-530515, and platinum complexes described in Adv. Mater. 2014, 26, 7116 or Japanese Patent Publication No. 2018-2722 are preferred, but not limited to these.

[0121] There are no particular limitations on phosphorescent dopant materials; the following examples can be cited.

[0122] [Chemistry 22]

[0123]

[0124] [Chemistry 23]

[0125]

[0126] In the case of using a fluorescent light-emitting dopant as the light-emitting dopant material, there is no particular limitation as the fluorescent light-emitting dopant, and for example, condensed polycyclic aromatic derivatives, styrylamine derivatives, condensed cyclic amine derivatives, boron-containing compounds, pyrrole derivatives, indole derivatives, carbazole derivatives, and the like can be exemplified. Among these, condensed cyclic amine derivatives, boron-containing compounds, and carbazole derivatives are preferable. As the condensed cyclic amine derivatives, for example, diamine pyrene derivatives, diaminochrysene derivatives, diaminanthracene derivatives, diaminofluorenone derivatives, diaminofluorene derivatives having one or more benzofuran skeletons in the condensed ring, and the like can be exemplified.

[0127] As the boron-containing compound, for example, pyrromethene derivatives, polycyclic aromatic compounds described in WO2015 / 102118, and the like can be exemplified.

[0128] The fluorescent light-emitting dopant material is not particularly limited, and the following examples can be exemplified.

[0129] [Chemical Formula 24]

[0130]

[0131] [Chemical Formula 25]

[0132]

[0133] In the case of using a thermally activated delayed fluorescent light-emitting dopant as the light-emitting dopant material, there is no particular limitation as the thermally activated delayed fluorescent light-emitting dopant, and for example, thermally activated delayed fluorescent light-emitting dopants containing boron atoms, or metal complexes such as tin complexes or copper complexes, cyano benzene derivatives described in Nature 2012, 492, 234, carbazole derivatives, phenoxazine derivatives described in Nature Photonics 2014, 8, 326, oxadiazole derivatives, triazole derivatives, sulfone derivatives, phenoxazine derivatives, acridine derivatives, polycyclic aromatic compounds described in WO2015 / 102118, and the like can be exemplified.

[0134] The thermally activated delayed fluorescent light-emitting dopant material is not particularly limited, and the following examples can be exemplified. A cyclic azine compound can be used in the thermally activated delayed fluorescent light-emitting dopant material, but a compound represented by the general formula (10) is preferable.

[0135] [Chemical Formula 26]

[0136]

[0137] As the host material in the light-emitting layer, it is preferable to use the compound represented by the general formula (1) and / or general formula (10). In the case where the compound represented by the general formula (1) or general formula (10) is used in any organic layer other than the light-emitting layer, the compound represented by the general formula (1) or general formula (10) can or can not be contained in the light-emitting layer. At this time, a known host material used in a phosphorescent light-emitting element or a fluorescent light-emitting element can also be used in combination in the light-emitting layer. Furthermore, a plurality of known host materials can be used in combination, or each can be used alone. As the known host material that can be used, a compound having a hole-transporting ability, an electron-transporting ability, and having a high glass transition temperature, and preferably having a triplet excitation energy (T1) larger than that of the light-emitting dopant material. In addition, a compound having TADF activity can also be used as the host material, in which case, a compound having a difference (ΔEST = S1 - T1) between the singlet excitation energy (S1) and the triplet excitation energy (T1) of 0.20 eV or less is preferable. In addition, the compound represented by the general formula (1) can be contained alone as the host material in the light-emitting layer in combination with other known host materials, but in order to improve the characteristics of the organic EL element, it is necessary to use the compound represented by the general formula (10) as the host material in combination. In addition, a plurality of known host materials other than the compound represented by the general formula (10) can also be used in combination.

[0138] Here, S1, T1 are measured in the following manner.

[0139] A sample compound (thermally activated delayed fluorescence material) was vacuum-deposited on a quartz substrate under a condition of a vacuum degree of 10 -4 A deposition film was formed in a thickness of 100 nm by vacuum deposition of the sample compound (thermally activated delayed fluorescence material) under a condition of a vacuum degree of 10 S1 was calculated by substituting the value of the wavelength into the formula (i) shown below.

[0140]

[0141] On the other hand, with respect to T1, the phosphorescence spectrum of the deposition film was measured, and a tangent line was drawn to the rising edge on the short wavelength side of the phosphorescence spectrum, and the wavelength value of the intersection of the tangent line and the horizontal axis was measured. T1 was calculated by substituting the value of the wavelength into the formula (ii) shown below.

[0142]

[0143] Known host materials are known from a large number of patent documents and the like, and thus can be selected from among these. Specific examples of the host material are not particularly limited, and various metal complexes represented by, for example, indole compounds, carbazole compounds, pyridine compounds, pyrimidine compounds, triazine compounds, triazole compounds, oxazole compounds, oxadiazole compounds, imidazole compounds, phenylenediamine compounds, arylamine compounds, anthracene compounds, fluorenone compounds, stilbene compounds, triphenylene compounds, carborane compounds, porphyrin compounds, metallophthalocyanine, metal complexes of 8-hydroxyquinoline compounds or metallophthalocyanines, metal complexes of benzoxazole or benzothiazole compounds; poly(N-vinylcarbazole) compounds, aniline-based copolymer compounds, thiophene oligomers, polythiophene compounds, polyaniline compounds, polyanilinevinylene compounds, polyfluorene compounds, and the like. Among these, carbazole compounds, indolocarbazole compounds, pyridine compounds, pyrimidine compounds, triazine compounds, anthracene compounds, triphenylene compounds, carborane compounds, and porphyrin compounds are preferable.

[0144] The known host material is not particularly limited, and specific examples include the following.

[0145] [Chem. 27]

[0146]

[0147] [Chem. 28]

[0148]

[0149] In the case of using a plurality of hosts, each host can be vapor-deposited from a different vapor deposition source, or a premix can be prepared by pre-mixing before vapor deposition, and thus a plurality of hosts can be simultaneously vapor-deposited from one vapor deposition source.

[0150] In the case of using a plurality of hosts, the host is preferably a mixed composition (premix) for the organic electroluminescent device, which is obtained by mixing the compound represented by the general formula (1) and the compound represented by the general formula (10).

[0151] In the case of using a plurality of hosts, in order to reproducibly produce an organic EL element having good characteristics, it is desirable that the 50% weight reduction temperatures (T 50The difference between the 50% weight reduction temperatures of the two hosts is preferably within 20°C. By vapor deposition from a single evaporation source, a uniform vapor deposition film can be obtained. At this time, a light-emitting dopant material required to form a light-emitting layer or other hosts as necessary can also be mixed in the pre-mixture, but in the case where there is a large difference in temperature at which the desired vapor pressure is obtained, vapor deposition can also be performed from another vapor deposition source.

[0152] The difference between the 50% weight reduction temperatures of the two hosts in the pre-mixture is preferably within 20°C. By vapor deposition from a single evaporation source, a uniform vapor deposition film can be obtained. At this time, a light-emitting dopant material required to form a light-emitting layer or other hosts as necessary can also be mixed in the pre-mixture, but in the case where there is a large difference in temperature at which the desired vapor pressure is obtained, vapor deposition can also be performed from another vapor deposition source.

[0153] In addition, with respect to the mixing ratio (mass ratio) of the first host to the second host when two hosts are used, the proportion of the first host with respect to the total of the first host and the second host can be 40% to 90%, preferably 50% to 90%, and more preferably 60% to 90%. In the case where the compound represented by the general formula (1) is used as a host, the first host is the compound represented by the general formula (1), and the compound represented by the general formula (10) is the second host.

[0154] As the method of pre-mixing, as described above, a method in which mixing is as uniform as possible is desirable, and pulverization mixing, or a method in which heating and melting is performed under reduced pressure or in an inert gas atmosphere such as nitrogen, or sublimation, etc. can be cited, but are not limited to these methods.

[0155] In addition, the form of the host and the pre-mixture thereof can be a powder, a rod, or a granule.

[0156] - Injection Layer -

[0157] The injection layer is a layer provided between an electrode and an organic layer in order to reduce the driving voltage or increase the luminance of light emission, and is a hole injection layer and an electron injection layer, and can be present between an anode and a light-emitting layer or a hole transport layer, and between a cathode and a light-emitting layer or an electron transport layer. The injection layer can be provided as necessary.

[0158] - Hole Blocking Layer -

[0159] The hole blocking layer, in a broad sense, has the function of an electron transport layer, and contains a hole blocking material that has the function of transporting electrons and has a significantly small ability to transport holes. The hole blocking layer can improve the probability of recombination of electrons and holes in the light emitting layer by transporting electrons and blocking holes. In the hole blocking layer, a known hole blocking material can be used. In addition, a plurality of hole blocking materials can be used in combination.

[0160] - electron blocking layer -

[0161] The electron blocking layer, in a broad sense, has the function of a hole transport layer, and can improve the probability of recombination of electrons and holes in the light emitting layer by transporting holes and blocking electrons. As the material of the electron blocking layer, a compound represented by the general formula (1) or the mixed material can be used, but a known electron blocking layer material can also be used. In addition, in the case where the compound represented by the general formula (1) or the mixed material is used for the electron blocking layer, as the host material, a compound represented by the general formula (1), a known host material described in the description, and a host material composed of a plurality of these can be used.

[0162] As the layer adjacent to the light emitting layer, there are a hole blocking layer, an electron blocking layer, and the like, and in the case where these layers are not provided, a hole transport layer, an electron transport layer, and the like become the adjacent layer.

[0163] - hole transport layer -

[0164] The hole transport layer contains a hole transport material having the function of transporting holes, and the hole transport layer can be provided as a single layer or a plurality of layers.

[0165] As the hole transport material, a material having any one of the functions of injecting or transporting holes and blocking electrons can be used, and can be any one of an organic material and an inorganic material. As the hole transport material, any one of the previously known compounds can be used. As the hole transport material, for example, a porphyrin derivative, a triazole derivative, an oxadiazole derivative, an imidazole derivative, a polyarylalkane derivative, a phenylenediamine derivative, an arylamine derivative, an amino-substituted chalcone derivative, an oxazole derivative, a styrylanthracene derivative, a fluorenone derivative, a hydrazone derivative, a stilbene derivative, a silazane derivative, an aniline-based copolymer, and a conductive polymer oligomer, particularly a thiophene oligomer, and the like can be listed.

[0166] - electron transport layer -

[0167] The electron transport layer contains a material having the function of transporting electrons, and the electron transport layer can be provided as a single layer or a plurality of layers.

[0168] As the electron-transporting material (which sometimes also functions as a hole-blocking material), it is only required to have a function of transporting the electrons injected from the cathode to the light-emitting layer. The electron-transporting layer can be used with any of the compounds known heretofore, and examples thereof include polycyclic aromatic derivatives such as naphthalene, anthracene, phenanthroline, etc., tris(8-hydroxyquinoline)aluminum (III) derivatives, phosphine oxide derivatives, nitro-substituted fluorene derivatives, diphenylquinone derivatives, dioxothiopyran derivatives, carbodiimide derivatives, fluorenylidene methane derivatives, anthraquino dimethane and anthrone derivatives, bipyridine derivatives, quinoline derivatives, oxadiazole derivatives, benzimidazole derivatives, benzothiazole derivatives, indolocarbazole derivatives, etc. Further, a high molecular material in which any of these materials is introduced into a high molecular chain or which has any of these materials as a main chain of the high molecule can also be used.

[0169] The method for forming each layer in the production of the organic EL element of the present application is not particularly limited, and any of a dry process and a wet process can be used.

[0170] Examples

[0171] The present application will be described in more detail below by way of examples, but the present application is not limited to these examples.

[0172] The compounds used in the examples and comparative examples are shown below.

[0173] [Chemical Formula 29]

[0174]

[0175] [Chemical Formula 30]

[0176]

[0177] Comparative Example 1

[0178] On a glass substrate having an ITO-containing anode with a film thickness of 70 nm, a 50-nm-thick layer of N,N'-diphenyl-N,N'-bis(1-naphthyl)-1,1'-biphenyl-4,4'-diamine (NPB) was formed by a vacuum evaporation method at a vacuum degree of 4.0 x 10 -5The following films were stacked under Pa. First, HAT-CN shown above was formed to a thickness of 10 nm on ITO as a hole injection layer, and then HT-1 was formed to a thickness of 60 nm as a hole transport layer. Next, HT-2 was formed to a thickness of 5 nm as an electron blocking layer. Then, co-evaporation of the compound (1-42) as the host, and BD-2 as a phosphorescent light-emitting dopant, and BD-1 as a thermally activated delayed fluorescence light-emitting dopant was performed from separate evaporation sources, to form a light-emitting layer having a thickness of 40 nm. At this time, the co-evaporation was performed under evaporation conditions in which the concentration of BD-2 was 13% by mass and the concentration of BD-1 was 0.4% by mass. Next, ET-2 was formed to a thickness of 5 nm as a hole blocking layer. Next, ET-2 was formed to a thickness of 31 nm as an electron transport layer. Further, lithium fluoride (LiF) was formed to a thickness of 1 nm on the electron transport layer as an electron injection layer. Finally, aluminum (Al) was formed to a thickness of 70 nm on the electron injection layer as a cathode, thereby producing an organic EL element of Comparative Example 1.

[0179] Comparative Example 2

[0180] An organic EL element was produced in the same manner as in Comparative Example 1, except that the host was changed to HT-2, as shown in Table 1.

[0181] Example 1

[0182] On a glass substrate having an anode comprising ITO with a film thickness of 70 nm, a light-emitting layer was formed by a vacuum evaporation method at a vacuum degree of 4.0 x 10 -5The following films were stacked under Pa. First, HAT-CN shown above was formed to a thickness of 10 nm on ITO as a hole injection layer, and then HT-1 was formed to a thickness of 60 nm as a hole transport layer. Next, HT-2 was formed to a thickness of 5 nm as an electron blocking layer. Then, co-evaporation of the compound (1-30) as a first host, the same compound (2-49) as a second host, and BD-2 as a phosphorescent light-emitting dopant, and BD-1 as a thermally activated delayed fluorescence light-emitting dopant was performed from separate evaporation sources to form a light-emitting layer having a thickness of 40 nm. At this time, the co-evaporation was performed under evaporation conditions in which the concentration of BD-2 was 13 mass%, the concentration of BD-1 was 0.4 mass%, and the mass ratio of the first host to the second host was 50:50. Next, ET-2 was formed to a thickness of 5 nm as a hole blocking layer. Next, ET-2 was formed to a thickness of 31 nm as an electron transport layer. Further, lithium fluoride (LiF) was formed to a thickness of 1 nm on the electron transport layer as an electron injection layer. Finally, aluminum (Al) was formed to a thickness of 70 nm on the electron injection layer as a cathode, thereby producing an organic EL element of Example 1. The evaluation results are shown in Table 2.

[0183] Examples 2 to 23, Comparative Examples 3 to 9

[0184] An organic EL element was produced in the same manner as in Example 1, except that the electron blocking layer material, the first host, and the second host were the compounds shown in Table 1. The evaluation results are shown in Table 2.

[0185] [Table 1]

[0186]

[0187] [Table 2]

[0188]

[0189] The organic EL elements obtained in the examples and comparative examples were connected to an external power source and a direct current voltage was applied, and as a result, in all of the organic EL elements, an emission spectrum of a maximum emission wavelength of 450 nm to 480 nm was observed, and thus emission from BD-1 was obtained.

[0190] From the results of the examples and comparative examples shown in Table 2, it was found that the organic EL element in which the mixed material for an organic electroluminescent element of the present application was used as a host in the light-emitting layer emitted blue light, and had characteristics of low voltage, high efficiency, and long lifetime. In addition, the voltage and the power efficiency in the table are values at a driving current of 2.5 mA / cm 2 2, and are initial characteristics. In addition, the lifetime is a value at a driving current of 4.0 mA / cm2 The time taken for the initial luminance to decay to 97% when the initial luminance is set to 100% indicates the lifetime characteristics. In addition, the emission color was confirmed using the emission spectrum of the organic electroluminescent element.

[0191] Comparative Example 10

[0192] On a glass substrate on which an anode comprising ITO having a film thickness of 70 nm was formed, each thin film shown below was laminated by a vacuum evaporation method at a vacuum degree of 4.0 x 10 -5 First, HAT-CN shown above was formed as a hole injection layer to a thickness of 10 nm on ITO, and then HT-1 was formed as a hole transport layer to a thickness of 60 nm. Next, HT-2 was formed as an electron blocking layer to a thickness of 5 nm. Then, co-evaporation of compound (1-42) as a first host and BD-2 as a phosphorescent light-emitting dopant was performed from separate evaporation sources to form a light-emitting layer having a thickness of 40 nm. At this time, co-evaporation was performed under evaporation conditions in which the concentration of BD-2 was 13 mass%. Next, ET-2 was formed as a hole blocking layer to a thickness of 5 nm. Next, ET-2 was formed as an electron transport layer to a thickness of 31 nm. Further, lithium fluoride (LiF) was formed as an electron injection layer to a thickness of 1 nm on the electron transport layer. Finally, aluminum (Al) was formed as a cathode to a thickness of 70 nm on the electron injection layer, thereby producing an organic EL element of Comparative Example 10. The evaluation results are shown in Table 4.

[0193] Comparative Example 11

[0194] An organic EL element was produced in the same manner as in Comparative Example 10 except that the host was changed to HT-2, as shown in Table 3. The evaluation results are shown in Table 4.

[0195] Examples 24 to 46 and Comparative Examples 12 to 18

[0196] An organic EL element was produced in the same manner as in Comparative Example 10 except that the electron blocking layer material, the first host, and the second host were changed to the compounds shown in Table 3. The evaluation results are shown in Table 4.

[0197] [Table 3]

[0198]

[0199] [Table 4]

[0200] [Table 4]

[0201]

[0202] From the results of the examples and comparative examples shown in Table 4, it was found that the organic EL element using the mixed material for organic electroluminescent element according to the present application as the host in the light-emitting layer emits blue light, and has the characteristics of low voltage, high efficiency, and long lifetime. Further, various evaluations were performed in the same manner as described above, and it was found that the emission spectrum of the emission having a maximum wavelength of 450 nm to 480 nm was observed, and thus the emission from BD-2 was obtained.

[0203] Industrial Applicability

[0204] According to the present application, an organic EL element which is practically useful, has the characteristics of low voltage driving, emits light with high efficiency, and has long lifetime can be obtained.

[0205] Explanation of Reference Numerals

[0206] 1: substrate

[0207] 2: anode

[0208] 3: hole injection layer

[0209] 4: hole transport layer

[0210] 5: light-emitting layer

[0211] 6: electron transport layer

[0212] 7: cathode

Claims

1. A mixture material for an organic electroluminescent element, characterized by comprising: a compound represented by the following general formula (1), and a cyclic azine compound represented by the following general formula (10), [Chemical Formula 1] (wherein, m represents the number of repetitions and is 2 or 3; Ar 1 represents an aliphatic hydrocarbon group having 1 to 10 carbons, a substituted or unsubstituted triaryl silyl group having 18 to 36 carbons, a substituted or unsubstituted aromatic hydrocarbon group having 6 to 20 carbons, a substituted or unsubstituted aromatic heterocyclic group having 2 to 20 carbons, or a substituted or unsubstituted linked aromatic group formed by linking 2 to 3 aromatic groups selected from the aromatic hydrocarbon group and the aromatic heterocyclic group; R 2 ~R 7 independently represent hydrogen, an aliphatic hydrocarbon group having 1 to 10 carbons, a substituted or unsubstituted triaryl silyl group having 18 to 36 carbons, a substituted or unsubstituted aromatic hydrocarbon group having 6 to 20 carbons, a substituted or unsubstituted aromatic heterocyclic group having 2 to 20 carbons, or a substituted or unsubstituted linked aromatic group formed by linking 2 to 3 aromatic groups selected from the aromatic hydrocarbon group and the aromatic heterocyclic group; wherein, Ar 1 and R 2 ~R 7 does not include carbazole; in addition, a part or all of the hydrogens in the compound represented by General Formula (1) can be substituted with deuterium) ; [Chemical Formula 2] (Here, Ar 2 and Ar 3 independently represent an aliphatic hydrocarbon group having 1 to 10 carbons, a substituted or unsubstituted triaryl silyl group having 18 to 36 carbons, a substituted or unsubstituted aromatic hydrocarbon group having 6 to 20 carbons, a substituted or unsubstituted aromatic heterocyclic group having 2 to 17 carbons, or a substituted or unsubstituted linked aromatic group formed by linking 2 to 3 aromatic groups selected from the aromatic hydrocarbon group and the aromatic heterocyclic group; L 1 represents a single bond or a substituted or unsubstituted phenyl group; and some or all of the hydrogens in the compound represented by the general formula (10) can be substituted with deuterium).

2. The mixture material according to claim 1, wherein The compound represented by the general formula (1) contains at least one of a bond structure represented by any one of the following formulas (2) to (7), [Chemical Formula 3] Some or all of the hydrogens in the bonding structure represented by Formula (2) to Formula (7) can be substituted with deuterium; represents the bonding position with the carbazole or Ar 1 in the general formula (1).

3. The mixture material according to claim 1, wherein The compound represented by the general formula (1) contains at least one of the bond structures represented by the formula (2) or (3).

4. The mixture material according to claim 1, wherein The compound represented by the general formula (1) contains at least one of the bond structures represented by the formula (4) or (5).

5. The mixture material according to claim 1, wherein The compound represented by the general formula (1) contains at least one of the bond structures represented by the formula (6) or (7).

6. The mixture material according to claim 1, wherein The compound represented by the general formula (1) contains at least two of the bond structures represented by the formulas (2) to (7).

7. The mixture material according to claim 1, wherein L in the general formula (10) is a single bond. 1 a single bond.

8. An organic electroluminescent element comprising one or more organic layers between a pair of an anode and a cathode, characterized in that at least one of the organic layers contains the mixed material for an organic electroluminescent element according to claim 1.

9. The organic electroluminescent device according to claim 8, wherein The organic layer containing the mixed material for an organic electroluminescent element is a light-emitting layer, and the light-emitting layer contains a thermally activated delayed fluorescence light-emitting material.

10. The organic electroluminescent device according to claim 9, wherein The organic layer containing the mixed material for an organic electroluminescent element is a light-emitting layer, and the light-emitting layer contains a thermally activated delayed fluorescence light-emitting material containing a boron atom.

11. The organic electroluminescent device according to claim 8, wherein The organic layer containing the mixed material for an organic electroluminescent element is a light-emitting layer, and the light-emitting layer contains a phosphorescent light-emitting material.

12. The organic electroluminescent device according to claim 11, wherein The organic layer containing the mixed material for an organic electroluminescent element is a light-emitting layer, and the light-emitting layer contains a phosphorescent light-emitting material containing a platinum atom.

13. The organic electroluminescent device according to claim 8, wherein The organic layer containing the mixed material for an organic electroluminescent element is a light-emitting layer, and the light-emitting layer contains a thermally activated delayed fluorescence light-emitting material containing a boron atom and a phosphorescent light-emitting material containing a platinum atom.

14. The organic electroluminescent device according to any one of claims 8 to 13, wherein The light-emitting layer contains the mixed material for an organic electroluminescent element according to claim 1 as a host material.

15. A method for manufacturing an organic electroluminescent element, which is a method for manufacturing an organic electroluminescent element having a plurality of organic layers between an anode and a cathode, characterized by One of the organic layers is a light-emitting layer, and the light-emitting layer is produced by using the mixed material for an organic electroluminescent element according to claim 1 to make a premix and evaporating the premix from one evaporation source.

Images